Re: [PATCH v2 3/4] perf record: apply affinity masks when reading mmap buffers

[Alexey Budankov]

Hi,

On 02.01.2019 0:39, Jiri Olsa wrote:
> On Mon, Dec 24, 2018 at 03:27:17PM +0300, Alexey Budankov wrote:
>>
>> Build node cpu masks for mmap data buffers. Apply node cpu
>> masks to tool thread every time it references data buffers
>> cross node or cross cpu.
>>
>> Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
>> ---
>> Changes in v2:
>> - separated AIO buffers binding to patch 2/4
>> ---
>>  tools/perf/builtin-record.c |  9 +++++++++
>>  tools/perf/util/evlist.c    |  6 +++++-
>>  tools/perf/util/mmap.c      | 12 ++++++++++++
>>  tools/perf/util/mmap.h      |  1 +
>>  4 files changed, 27 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index b26febb54d01..eea96794ee45 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -536,6 +536,9 @@ static int record__mmap_evlist(struct record *rec,
>>  	struct record_opts *opts = &rec->opts;
>>  	char msg[512];
>>  
>> +	if (opts->affinity != PERF_AFFINITY_SYS)
>> +		cpu__setup_cpunode_map();
>> +
>>  	if (perf_evlist__mmap_ex(evlist, opts->mmap_pages,
>>  				 opts->auxtrace_mmap_pages,
>>  				 opts->auxtrace_snapshot_mode,
>> @@ -755,6 +758,12 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
>>  		struct perf_mmap *map = &maps[i];
>>  
>>  		if (map->base) {
>> +			if (rec->opts.affinity != PERF_AFFINITY_SYS &&
>> +			    !CPU_EQUAL(&rec->affinity_mask, &map->affinity_mask)) {
>> +				CPU_ZERO(&rec->affinity_mask);
>> +				CPU_OR(&rec->affinity_mask, &rec->affinity_mask, &map->affinity_mask);
>> +				sched_setaffinity(0, sizeof(rec->affinity_mask), &rec->affinity_mask);
> 
> all this code depends on aio and LIBNUMA, let's keep it there then

Please note that thread migration improves performance for serial case too:

			       BENCH REPORT BASED   ELAPSED TIME BASED
	  v4.20.0-rc5 
          (tip perf/core):
				
(current) SERIAL-SYS  / BASE : 1.27x (14.37/11.31), 1.29x (15.19/11.69)
	  SERIAL-NODE / BASE : 1.15x (13.04/11.31), 1.17x (13.79/11.69)
	  SERIAL-CPU  / BASE : 1.00x (11.32/11.31), 1.01x (11.89/11.69)

mbind() for AIO buffers is the only related adjustment.

> 
> also please add this and the affinity_mask setup code below to a function

Separated the code into record__adjust_affinity() and perf_mmap__setup_affinity_mask() in v3.

Thanks,
Alexey

> 
> thanks,
> jirka
> 
>> +			}
>>  			if (!record__aio_enabled(rec)) {
>>  				if (perf_mmap__push(map, rec, record__pushfn) != 0) {
>>  					rc = -1;
>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
>> index 60e825be944a..5ca5bb5ea0db 100644
>> --- a/tools/perf/util/evlist.c
>> +++ b/tools/perf/util/evlist.c
>> @@ -1028,7 +1028,11 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
>>  	 * Its value is decided by evsel's write_backward.
>>  	 * So &mp should not be passed through const pointer.
>>  	 */
>> -	struct mmap_params mp = { .nr_cblocks = nr_cblocks, .affinity = affinity };
>> +	struct mmap_params mp = {
>> +		.nr_cblocks 	= nr_cblocks,
>> +		.affinity 	= affinity,
>> +		.cpu_map 	= cpus
>> +	};
>>  
>>  	if (!evlist->mmap)
>>  		evlist->mmap = perf_evlist__alloc_mmap(evlist, false);
>> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
>> index 742fa9a8e498..a2095e4eda4b 100644
>> --- a/tools/perf/util/mmap.c
>> +++ b/tools/perf/util/mmap.c
>> @@ -361,6 +361,7 @@ void perf_mmap__munmap(struct perf_mmap *map)
>>  
>>  int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu)
>>  {
>> +	int c, nr_cpus, node;
>>  	/*
>>  	 * The last one will be done at perf_mmap__consume(), so that we
>>  	 * make sure we don't prevent tools from consuming every last event in
>> @@ -389,6 +390,17 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int c
>>  	map->cpu = cpu;
>>  
>>  	CPU_ZERO(&map->affinity_mask);
>> +	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1) {
>> +		nr_cpus = cpu_map__nr(mp->cpu_map);
>> +		node = cpu__get_node(map->cpu);
>> +		for (c = 0; c < nr_cpus; c++) {
>> +			if (cpu__get_node(c) == node) {
>> +				CPU_SET(c, &map->affinity_mask);
>> +			}
>> +		}
>> +	} else if (mp->affinity == PERF_AFFINITY_CPU) {
>> +		CPU_SET(map->cpu, &map->affinity_mask);
>> +	}
>>  
>>  	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
>>  				&mp->auxtrace_mp, map->base, fd))
>> diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
>> index e566c19b242b..b3f724fad22e 100644
>> --- a/tools/perf/util/mmap.h
>> +++ b/tools/perf/util/mmap.h
>> @@ -72,6 +72,7 @@ enum bkw_mmap_state {
>>  struct mmap_params {
>>  	int			    prot, mask, nr_cblocks, affinity;
>>  	struct auxtrace_mmap_params auxtrace_mp;
>> +	const struct cpu_map	    *cpu_map;
>>  };
>>  
>>  int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd, int cpu);
>